Quality loss when rendering in H.264 or even AVI RAW
Assuming you didn't miss anything obvious (wrong resolution) I would recommend to render it out with a really high bitrate (24300k) and then use handbrake to compress it in a useful manner. The default bitrate of 6k is just way to low.



Also there may be a blur node hiding in your setup. Looking closely at the ladder on top of the mast it seems like everything is spread out by one pixel.(left original, right encoded)